JPMorgan CEO Jamie Dimon thinks the global economy could be in for some choppy waters ahead as central banks curtail their massive bond-buying programs.

The US Federal Reserve, the European Central Bank, and the Bank of Japan have built up a combined balance sheet of nearly $14 trillion in assets. Dimon said at a conference in Paris on Tuesday that rolling back quantitative easing, in which central banks loaded up on trillions in assets to stabilize economies amid the global recession, was an unprecedented challenge and no one really knew how it would play out, according to a Bloomberg report.

"We've never have had QE like this before, we've never had unwinding like this before," Dimon said at the conference. "Obviously that should say something to you about the risk that might mean, because we've never lived with it before."

The Fed alone owns $4.5 trillion in assets it wants to start selling off this year. Fed officials have gone out of their way to give traders clarity into their expectations for balance-sheet reduction so as to avoid upsetting markets, but how the process will unfold is still uncertain.

Dimon said the process could roil a variety of markets as all the traditional buyers of sovereign debt in the past decade begin selling assets at the same time.

"When that happens of size or substance, it could be a little more disruptive than people think," Dimon said. "We act like we know exactly how it's going to happen, and we don't."